Can anyone recomend a small cheap bandsaw, desk mounted, that will handle cutting 3-4mm steel?
Horizontal or vertical? To handle that thickness you will need something quite big and a coolant feed would be necessary.
As above you'll need something pretty decent for 4mm steel. For a small job you might be better off with a jigsaw and going slow. For a bigger job you'll need to spend some money and it won't be desktop.
For one-offs just use a hacksaw.
Otherwise it won't be cheap, although if it's just cutting across lengths then one of the Evolution mitre saws will work and a grinder to smooth it out?
Good point. I was assuming you want curved cuts but if it's straight there's quite a few options.
If you're cutting shapes rather than straight lines then 3mm is at the upper end of the capacity of a nibbler. A Makita JN3200 or JN3201 would cost about £400 but its a model thats been around for a long time (surpassed by plasma cutters really) so you might be able to get a second hand one for a good price. Don't bother with air powered nibblers though.
it is for curved bit and 3mm will probably be the thickest.
Seen a small proxxon where their advertising pictures how them cutting a bolt in half length wise but not sure i trust that.
but will probably just stick to hacksaw and files